THz radiation can penetrate most of non-polarity dielectric, so the THz radiation can be acted as information carrier in imaging technology. In THz imaging technology, time waveform of THz pulse of each measure point of sample is recorded, then spectrum information of the measure point is obtained from Fourier transform of the time waveform. Therefore, not only contour but also components of the sample can be obtained from THz imaging technology. Moreover, refractive index distribution (depth distribution) can be calculated from time interval (phase change) of THz pulse.
Transmission mode or reflection mode is used in the THz imaging technology of prior art, and 2D image of sample can be obtained. Furthermore, 3D structure information of the sample can be obtained from time interval of the reflected THz pulse or by computer-aided tomography. But the THz imaging technology of prior art has not intrinsic 3D imaging ability.
Although real 3D image of sample by utilizing THz technology is desired, this technical difficulty is not solved so far.
This invention intends to provide a device and a method for THz imaging to solve the problem above.